perf tools: Dont stop PMU parsing on alias parse error

[ Upstream commit 940db6dcd3f4659303fdf6befe7416adc4d24118 ]

When an error happens during alias parsing currently the complete
parsing of all attributes of the PMU is stopped. This is breaks old perf
on a newer kernel that may have not-yet-know alias attributes (such as
.scale or .per-pkg).

Continue when some attribute is unparseable.

This is IMHO a stable candidate and should be backported to older
versions to avoid problems with newer kernels.

v2: Print warnings when something goes wrong.
v3: Change warning to debug output

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: stable@vger.kernel.org # v3.6+
Link: http://lkml.kernel.org/r/1455749095-18358-1-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index e243ad962a4d8876aecaafccf18858df2e52118f..bc7ca4ffcd2d0aa992c91738ea0c9f749de60c72 100644 (file)
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -221,13 +221,12 @@ static int pmu_aliases_parse(char *dir, struct list_head *head)
 {
        struct dirent *evt_ent;
        DIR *event_dir;
-       int ret = 0;
 
        event_dir = opendir(dir);
        if (!event_dir)
                return -EINVAL;
 
-       while (!ret && (evt_ent = readdir(event_dir))) {
+       while ((evt_ent = readdir(event_dir))) {
                char path[PATH_MAX];
                char *name = evt_ent->d_name;
                FILE *file;
@@ -243,17 +242,19 @@ static int pmu_aliases_parse(char *dir, struct list_head *head)
 
                snprintf(path, PATH_MAX, "%s/%s", dir, name);
 
-               ret = -EINVAL;
                file = fopen(path, "r");
-               if (!file)
-                       break;
+               if (!file) {
+                       pr_debug("Cannot open %s\n", path);
+                       continue;
+               }
 
-               ret = perf_pmu__new_alias(head, dir, name, file);
+               if (perf_pmu__new_alias(head, dir, name, file) < 0)
+                       pr_debug("Cannot set up %s\n", name);
                fclose(file);
        }
 
        closedir(event_dir);
-       return ret;
+       return 0;
 }
 
 /*